A. Field of Invention
This invention pertains to a support or frame structure made of at least two identical elements, each element having the shape of a parallelogram, the two elements being joined together in a manner that permits some pivoting of the elements about a diagonal axis.
B. Description of the Prior Art
A basic structural element used for many different purposes is a truss. A typical truss is formed of three linear rigid members, such as bars joined at their ends to form a triangle. Several trusses can be interconnected to form more complex three-dimensional support members. Trusses have been found to be very desirable structural elements because they can withstand large static and dynamic stresses and compressions without damage and are used in many different situations and common every-day objects, starting from relatively small objects such as small picture frames and stands, saw horses, and going all the way to large bridges and building sections.
In some situations support structures are required that can be folded for storage or shipping. For these situations, structures are used that include one or more joints that are either disassembled, or provided with hinges. However, these structures are generally expensive, less reliable, and, often, esthetically unacceptable.